The present invention relates to devices used to close or shut tubular members and, more particularly, to hemostatic clips used to close blood vessels within the body and to methods for manufacturing such hemostatic clips.
During many surgical procedures, the surgeon will have to close or ligate various blood vessels before severing the vessels in order to prevent excessive bleeding and reduce the risk to the patient of blood loss.
A prior technique to close a blood vessel is to ligate it; that is, tie a surgical suture about the vessel to close the vessel. Also, there are various types of metal devices or clips having a pair of legs connected at their proximal ends that can be placed about the vessel and the legs urged or squeezed together to shut the blood vessel. Very often the clip is notched at its proximal end where the legs meet to insure that when the legs are urged together the clip bends at the notch. Hemostatic clips are well known in the prior art and are disclosed in numerous U.S. Patents as, for example, Nos. 3,439,523, 3,270,745, 3,363,628, 3,463,156, 3,439,522, 3,439,523, and 4,146,130.
A serious problem with the prior art hemostatic clips is, though they may be closed about a blood vessel and shut off the flow of blood, there is very often a gap left in the closed clip.
The open clip comprises a pair of leg members connected at their proximal ends with their distal ends spaced apart. The open distal ends of the clip are placed about the vessel to be closed and using a suitable instrument the legs are urged together in an attempt to bring the distal ends in contact and place the legs substantially parallel and in uniform contact with the surface of the vessel. However, in practice the uniform contact is very seldom attained and instead there are spaces or areas of the leg of the clip which are in greater contact with the vessel than other spaces or areas of the clip. The areas with the lesser contact or pressure on the vessel are termed the gap. This gap very often allows the clip to move or slide along the length of the vessel about which it has been closed. When this happens, and the vessel has been cut, in many instances, the clip will slide off the cut end of the blood vessel thus allowing the flow of blood from the now unclosed vessel. The gap in part is caused by the construction of the clip in that the clip is designed so that the distal end of the leg members close first to entrap the vessel in the clip and prevent the vessel from slipping out of the clip on closing the leg members. The leg members are then urged toward each other to close the vessel. The gap is also in part a function of the yield strength of the metal used to form the clip. The higher the yield strength of the metal, the greater the possibility of forming a gap and the greater the size of the formed gap upon closing the clip. As previously mentioned, the gap is usually not sufficient so there is leakage of blood from the severed vessel; however, the gap is often sufficient to allow the clip to slide along the blood vessel. This can often happen when the surgeon or nurse is in the surgical area and is attempting to wipe blood or clean the operative area with a sponge and a corner of the sponge catches on the clip. If the gap is large enough the clip will slide on the vessel even to the point of being removed from the cut end of the vessel.
What we have discovered is an improved clip which has a minimal gap upon closing and, hence, more positively closes the vessel during the surgical procedure. Our new clips are made from metal such as stainless steel, tantalum, and the like.